Considerable evidence indicates that there is a transition between childhood and adolescence in taste preference for sweets. Although numerous hypotheses have been suggested to account for this change, little well- controlled research has investigated the contribution of puberty and its associated changes to this developmental transition . The purpose of this study is to assess several factors [i.e., steroid hormone levels, growth rate, alterations in taste sensitivity, and the genetically-determined ability to taste 6-n-propyl-thiouracil (PROP)] to determine how they are related to sucrose preference and perception. The specific aims of the proposed study are: 1) to determine whether a decrease in sucrose preference occurs following puberty in both males and females, 2) to determine whether taste sensitivity for sucrose is increased following puberty in both males and females, 3) to determine whether adolescents growing at a rapid rate have higher preferences for sucrose than do those growing t a slower rte, 4) to replicate a previous finding that children who have the genetically-determined ability to taste PROP have lower preferences for sucrose than do those who are non-tasters of PROP, and 5) to determine whether pubertal status interacts with PROP taster status in predicting sucrose preference in adolescents. These factors will be examined by testing sucrose preference, taste sensitivity, and eating habits in 180 adolescent males and females in the age range of 12 to 15 years. Growth rates in all subjects will be estimated from urinary markers of bone metabolism. Paper and pencil measures will be used to assess eating habits. There is considerable variability in the onset of puberty between the ages of 12 and 15 years. Pubertal status of males will be determined from salivary testosterone levels. Females will be categorized as pre- or post-menarche, with salivary hormone levels used to determine stage of the menstrual cycle. Thus, this study will examine the influence of puberty on sweet taste preference independently from the influence of chronological age. Two-year follow-up of f the participants will be conducted to assess the persistence of any observed effects, as well as to detect any delayed effects of puberty or PROP taster status on diet preference. High consumption of sugar impacts both systemic and oral health. Identification of the physiological mechanisms influencing sucrose preference should led to the ability to identify individuals most t risk for over-consuming sweets. This knowledge would help to target future outreach programs aimed at altering dietary habits.